Dental CBCT Scan: What It Is, When You Need One, Safety, and Cost

CBCT stands for cone beam computed tomography. During the scan, an X-ray source and detector rotate once around your head. The X-ray beam is shaped like a cone rather than the thin fan used in medical CT, so the machine can capture the whole region of interest in a single rotation. Software then reconstructs hundreds of thin image slices into a 3D volume that the surgeon can scroll through, rotate, and measure.

Traditional dental imaging is two-dimensional:

• Periapical X-rays show one or two teeth and their roots in detail.
• Bitewing X-rays show the crowns of back teeth and are used to detect decay.
• Panoramic X-rays show the whole jaw in one wide image and are excellent for screening wisdom teeth and missing teeth.

Two-dimensional images are fast, inexpensive, and involve very low radiation, which is why they remain the first choice for most dental care. Their limitation is that they overlap structures on top of one another and can distort distances. A panoramic image might show that a wisdom tooth root and the nerve canal overlap, but it cannot show whether the root is actually in front of, behind, or wrapped around the nerve. CBCT answers that question directly.

CBCT compared with other imaging

CBCT is recommended when three-dimensional information will meaningfully improve diagnosis, safety, or planning. It is not routine for every patient. Common reasons include:

Dental implant planning

Implants need to be placed in bone of sufficient height and width, at the correct angle for the final crown, and at a safe distance from the lower jaw nerve and the maxillary sinus. CBCT lets the surgeon measure the bone precisely at the planned implant site, identify whether a bone graft or sinus lift is needed, and choose the right implant size before surgery. At our office, CBCT data can be used to plan implant placement virtually and, when appropriate, to create a surgical template that helps guide placement with enhanced accuracy. Read more on our dental implants page.

Wisdom teeth close to the nerve or sinus

Lower wisdom teeth sometimes sit very close to the inferior alveolar nerve, which supplies feeling to the lower lip and chin. When a panoramic X-ray shows signs of a close relationship, CBCT shows the exact position of the roots relative to the nerve. That allows the surgeon to explain the risk accurately and, in some cases, change the surgical approach. Upper wisdom teeth can be assessed in relation to the sinus floor in the same way. See when wisdom teeth should be removed and our guide to impacted wisdom teeth.

Impacted canines and other unerupted teeth

For an impacted upper canine, it matters whether the tooth lies on the palate side or the cheek side, how it is angled, and whether it is pressing on the roots of neighbouring teeth. CBCT gives the surgeon and orthodontist this information to plan exposure surgery and the direction of orthodontic pull. See impacted canines.

Cysts, lesions, and jaw pathology

When an area of the jaw looks abnormal on a routine X-ray, CBCT shows its size, borders, and relationship to teeth, nerves, and the sinus. This helps decide whether a biopsy is needed and how to approach surgery. See oral pathology.

Facial trauma

CBCT images can be reconstructed into a three-dimensional representation of the facial bones, which is useful when assessing and planning treatment for some fractures and injuries. Acute major injuries are usually imaged in hospital.

Other uses

CBCT may also be used to assess the jaw joints, evaluate the airway in selected patients, locate extra teeth, check root fractures, and plan complex extractions.

• Routine checkups and cavity detection
• Most simple extractions of fully erupted teeth
• Wisdom teeth that are clearly well away from the nerve and sinus on a panoramic X-ray
• Screening "just in case" without a specific clinical question

The decision is always based on whether the added information justifies the radiation dose and cost. If a two-dimensional image is enough to plan your treatment safely, that is what your surgeon will use.

CBCT uses ionizing radiation, so it is only taken when there is a clear benefit. The actual dose depends on several factors:

• Field of view. A small scan of one area of the jaw uses much less radiation than a large scan of the whole face. Offices choose the smallest field of view that answers the clinical question.
• Machine settings. Resolution and exposure settings are adjusted for the task.
• Patient size and age. Children are more sensitive to radiation, so extra care is taken to limit exposure.

A dental CBCT scan generally delivers a lower dose than a conventional medical CT scan of the same region, and a focused, small-field scan is often comparable to a few days to a few weeks of natural background radiation, depending on the settings. Our office follows the ALARA principle, which means radiation exposure is kept as low as reasonably achievable for each scan.

Pregnancy and CBCT

Tell the team before your scan if you are or might be pregnant. Most non-urgent imaging is postponed until after pregnancy, and your surgeon will discuss the options with you.

The scan is quick and comfortable:

1. Consent and questions. You will review a CBCT consent form that explains why the scan is being taken, its benefits, the small radiation risk, alternatives such as 2D imaging, how the images will be interpreted, privacy, and fees.
2. Remove metal items. Earrings, necklaces, hairpins, glasses, hearing aids, and removable dentures or retainers are taken out, because metal creates streaks on the images.
3. Positioning. You stand or sit in the scanner. A chin rest or bite block keeps your head still, and a positioning light helps align the area of interest.
4. The scan. The machine rotates around your head. You need to stay completely still and avoid swallowing during the rotation, which usually lasts well under a minute.
5. Done. There is no recovery time. You can drive and return to normal activities immediately.

There are no injections, no dyes, and nothing enclosing your whole body, so CBCT is usually well tolerated by patients who feel claustrophobic in medical scanners.

Your surgeon reviews the images for the treatment question at hand. Because a CBCT volume includes more anatomy than the area being treated, a formal review of the entire scan by an oral and maxillofacial radiologist may be required. Depending on the case, the scan may be interpreted in-house or securely transmitted to a specialist radiology provider for a report. Specialist reports may take approximately 10 to 14 business days. Significant findings can be shared with your referring dentist for follow-up.

Alternatively, some patients are referred to an imaging centre where an oral radiologist takes the scan, interprets the images, and provides a comprehensive report.

CBCT imaging is not covered under provincial health care benefits in Ontario, and payment is required directly at the time of service. The fee usually depends on:

Some private dental insurance plans reimburse part of the cost of CBCT imaging, often depending on the reason for the scan. Ask the office for the procedure code and submit it to your insurer if you want to confirm coverage in advance. At our office, the scan and any required professional interpretation fee are the patient's responsibility at the time of service, regardless of insurance coverage, and we can provide receipts for your claim.

CBCT images are personal health information. In Ontario, they are handled according to the Personal Health Information Protection Act (PHIPA). With your authorization, images may be securely shared with your referring dentist or a radiology provider for diagnosis and treatment planning. You can ask how your data will be stored and shared.

Our office at 96 Union Street East, near Uptown Waterloo, has an in-office CBCT scanner, so many patients from Waterloo, Kitchener, Cambridge, Guelph, and Stratford can have their scan taken at the same location where their surgery is planned. This keeps planning efficient: the surgeon reviews the images, discusses the findings with you, and, for implants, can plan placement and a surgical guide from the same data.

Dr. Kevin J. McCann has provided oral and maxillofacial surgery in Kitchener-Waterloo since 1994, and Dr. Garry Toor has an extensive background in immediate implants, where precise 3D planning is especially valuable. If your dentist has recommended a 3D scan, call +1 (519)-743-7811, or ask them to send a referral. You can review the CBCT consent form and our 3D imaging page before your visit.

• 3D imaging and CBCT consent form, Dr. Kevin J. McCann Oral & Maxillofacial Surgery.
• Royal College of Dental Surgeons of Ontario, standards and guidance for dental radiography in Ontario.